Tube cleaning device



Sept. 7, 1943. K, MacK, URQUHART 2,328,865

TUBE GLANING DE-v-IGE Filed Nov. 4, 1941 B-Y @WM ATroRNEY Patented Sept.7,

'UNITED sinxrlazs PATENT OFI-ICE Kenneth Mackenzie Urquhm, New York, N.Y.,

assignor to Socony-'Vacuum Oil Company, Incorporated, New York, N. Y., acorporation of New York Application November 4, 1941, Serial No.417,768-

2 Claims. (Cl. l5-104.055)

l This invention relates to a device for cleaning tubes and is concernedparticularly with a rdevice for scavenging and cleaning tubes ar-4ranged in parallel by admitting a stream of high pressure cleaning iiuidto each of said tubes.

The invention, in one specific embodiment is admirably adapted forcleaning of perforated tubes such as are used in chambers for catalyticcracking of heavy mineral oil fractions to obtain products boilingwithin the range of gasoline. As shown in Patent No. 2,231,493, issuedFebruary 11, 1941, to Leland W. T. Cummings, a chamber of this type isnormally equipped with a plurality of inlet conduits and a plurality ofoutlet conduits extending into a body of granular catalytic' material,each of the conduits being in the form of a pipe, closed at the endembedded in the catalyst and having orifices at spaced points along itslength. The outlet or collector tubes are particularly subject tofouling of the orifices because the flow therethrough is from a regionin which carbonaceous matter isformedfrom the hydrocarbon vapors undertreatment. It is therefore necessary to clean the collector tubes fromtime to time by removing the top ofthe catalyst case to open the vaporspace above the tube sheet from which the collector tubes extend intothe catalyst bed.

The apparatus of this invention is designed to clean the tubes of a caseopened in the above manner rapidly and efIiciently. Means are providedwhereby air, steam or the.. likeis admitted to the ends of the collectortubes while said means are maintained in operative blowing relationshipwith said tubes by means of the pressure of the cleaning fluid. Theinvention also contemplates the provision of an apparatus whereby theoperative blowing relationship is established byreason ofsaid pressureafter adjustment of the apparatus to the desired position.

The nature of the inventionwill bemore fully understood from thedescription hereinafte when considered in connection with the annexeddrawing, wherein Figure 1 is a top plan view of a preferred form of theinvention;

Figure 2 is a sectional view on line .2-2 of Figure l;

Figure 3 is partial rear'elevation ofthe same device; and 1 Figure 4 isa detailed longitudinal section of the nozzle used in the apparatus.

The apparatus in its preferred form comprises three nozzles I forapplying a flow of cl 'steam to the collector tubes, the nozzles beingarranged relative to each other according to the arrangement of tubeswithin the catalyst case. The nozzles are carried on pipes Il extendingdownwardly from a casing I2 which denes a steam chest I3 in cooperationwith a cover plate Il, the casing and cover plate being securedtogether, as by bolts I5 and having a gasket I6, preferably of a metalsuch as aluminum, therebetween. Depending from the casing I2 andintegral therewith are a plurality of cylinders Il in each of which ismounted a hollow piston I8 having a shoulder I9 to engage the bottom ofthe steam chest and thereby limit outward movement of the piston. Thepiston I8 is further designed with a shoulder 20 and packing material 2lis maintained below said shoulder 20 between cylinder Il and tube I8under pressure applied through packing bushing 22 by a packing nut 23threaded on the lower portion of the piston I8. A pipe II is threadedinto the lower end of each piston I8 and carries a nozzle I0 at itslower end. The nozzle, as shown in Figure 4 is formed with a,dependingskirt 24 surrounding a nipple Attached to the top surface or the plate uare two guide members 21 formed to-flt on an Ibeam whereby the beam maybe utilized as an overhead track and backing element for the apparatus.A

o pair of handles 22 each welded to one of the pipes II are used formanual centering of the device over a set of three collector tubes to becleaned.

Means are also provided for manually retracting the pipes II and nozzlesI0 carried thereby after a blowing operation, which means comprises apair of levers 29 pivotally connected to -a sleeve-like retractor plate3l having as their fulcrums a pivotal connection with links 3|, thelatter being connected bypivot joints I2 to the casing. I2. It will beseen that an upward force exerted on the outer end of levers 29 will actthrough a link 23 on the lower surface of retractor plate 30 to forcepiston I8 upward and thus withdraw nozzles Il fromengagement with (i theends of collector tubes. In normal operation, D

lin-operation of the device, an I-beam is teml to reduce the sizethereof.

porarily installed above an opened catalyst vcase along a selected lineof pairs' of collector tube ends extending-above the tube sheet. Thecleaning device is then slidably mounted on the I-beam by engagement ofguide members 21 with the edges of the beam andthe device centered overa group of three collector tube ends and lowered to engagetherewith bymanual adjustment through use oi handles 2B. Steam is then admitted tosteam chest I3 under a pressure of 250 vto 300 pounds per square inchthrough an inlet port 318.v Steam will, of course, pass through thepipes II and the nozzles I to the collector tubes, a portion thereofleaking outbetween'the nozzles and collector tubes at the begimiing ofthe blow.

However, the pressure will exert a force -on the f The gaskets 26 areformed of rubber lor the likepreferably a synthetic rubber having a highpowerV of resistance ,to the deteriorating eifects ,of steam; since aleak, once developed, will rapidlyl enlarge'under the erosive action ofsteam passing therethrough at' high velocity, ending in complete'failureof the lasket. It is possible to use compressed air and thusavoid steamaction onthe-gasket, but this requires a very4 large compressor ifserious pressure drops during ,the blowing, are to be avoided. Whenusing 'air with the present apparatus,', 'a large storage tank' hasbeen' used, thus 'permitting the pressure to build up to a `prop erlevel between blowing of two sets ofthreetubes.

Illlponureference to Figure 2A it will be noted that the interiorcross*I sectional area of the conduit defined by piston` la isprogressively reduced from a, maximumat the outlet to chamber I3 t'o aat the point' of 'connection oi' pipe (I. Thua'the 'workixigfsmface ofeach piston i8 asaases suitable indicating mans be installed in thepressure line, changes in pressure and rate of now are very goodindications of cleanliness of tube orices. This avoids a separatetesting step and thepossibility the cleaning device may have to 'ofsaid-piston, a pipe attached to and depending from one end of saidpiston, a nozzle on the end of said pipe remote from said piston, saidnozzie terminating in 'a depending skirt about and 'spaced from a nippleand defining therewith an annular cavity and a resilient gasket in thebottom ot said cavity, said hollow piston defining a passagewayprogressively decreasing in cross sectional area between said chamberand said pipe, the greatest cross sectional area of the passageway beingless than the cross sectional area of the chamber and the least crosssectional area of the passageway being about equal to thevciosssectional area of the pipe, whereby the zone of greatest pressure willcause extension of the piston which, 'acting through the pipe, willsealV .the skirted end of the latter against a tube to be cleaned whilethe skirted end of said pipe will permit the use of a nipple of slightthickness so that variations in flow velocity between the pipe and thetube to be cleaned may be minimized and yet flow velocity may `bemaintained at a high value without leakage at the joint between the pipeand the tube to be cleaned.

2. Apparatus for cleaning tubes comprising, a plurality of cylinders, apiston in each cylinder,

. means for supplying a iluid under'pressure to isthe`sainelas''iftheopening Iinto chamber I3 wernoflthsam 'diameter as the 'ope'ning'intopipe f I I. -The pressure effect, however, is -quite diiferent in that.'under flow conditions.' velocity is progressively' increased in eachpiston I8 as the cross sectional yarea'of the'conduit defined thereby'isreduced.l rIhis, ofcourse, brings about a stage reductioninpressure. Thus, the total pressure exerted on each piston Il, when steamis flowingtherethrough, is not as great as if allof theworking surfaceslay in the same plane. The result of this is that there is -amplepressure to maintain a seal a't gasket 26 and yet the gasket is notdamaged by excessive Apressure while, of course, the desired increase innow velocity is attainable. On the other hand. if the tube to be cleanedis wholly clogged and the steam becomes static, the force exerted by thepiston on the gasket 26 can rise to a value equal to that attainablewith the same sizev piston having all working surfaces inthe same plane.

The device described' above is well suited to useI f\ in a combinedcleaning and testing apparatus.

each cylinder to cause extension of the piston therein, each pistonhaving a; fluid passageway therethrough. a pipe attached to anddepending from one end of each piston, said pipe constituting acontinuation of the passageway through the piston, means defining a seatfor a gasket at the end of each pipe remota from its point of attachmentto the respective piston, agasket in said seat adapted to bepressedagainst the end of a tube when the piston and pipe are extended.means denning an engaging surface on each piston and pipe unit, saidmeans lying the same distance below the top of each piston, a slidablesleeve' common to all the pipes and adapted to 61188.88 the engagingsurface to retract the pistons, whereby, when the pistons are extendedto diiferent degrees due to variations in the planes in which the endsof the pipes lie, they may be manually retracted to the same point byoperation of the means for moving the sleeve, which latter rst engagesthe engaging surface of the most extended piston and subsequently thoseoi the less extended pistons until all of the engaging surfaces areengaged, whereupon all voi' the pistons may be retracted for any desireddistance to lie in a single plane. v

KENNETH URQUHART.

